And they’ve made it happen. Although they spent the first winter hopping from pallet to pallet in a sea of mud, they got their first polytunnel up and started to propagate from the mother plants they’d brought with them. From the beginning, they tried to run the place in what they call an “environmentally aware” way. They don’t use peat in their compost and they collect rain to water the plants. It’s stored in 12 huge black 1,500-litre barrels, originally used to import orange juice. They even generate their own electricity, enough anyway to run the nursery and the office.

But how did they find customers, I wondered, tucked away as they are in the middle of nowhere? At first, explained Nigel, they did shows – Chelsea, Hampton Court, rare plant fairs. Now they do the internet. “It’s revolutionised our business” said Michelle. “When we first arrived here, the internet hadn’t really happened. Now 75 per cent of our business is mail order and most of that is online.” It’s a trend mirrored in recent research carried out by the Horticultural Trades Association, which shows that gardeners are now spending more online than they ever have before. Still, it surprises me. The Long Acre Plants website is excellent. It’s logical, well laid out and easy to use. The pictures of plants are gorgeous and there’s a generous amount of information about how to grow the things the nursery is offering.

But there is nothing quite like the feeling of wandering around a nursery for real, rather than in cyberspace. You don’t open up a website with the same eager anticipation as you approach a special plant nursery. The computer screen can tell you nothing about its setting. You can’t catch the damp, soft, sweet smell of many plants crowded together under cover. And for me, no second-hand, computer-generated experience, however clever, can replace the things you learn by having a plant in front of your own eyes: the texture of its foliage, the way it holds itself, its size (always deceptive in a photograph, when an anemone flower can seem as big as a dahlia).

A website is fine for ordering something you know you want, not so good for serendipitous discoveries. Long Acre’s online catalogue includes many wood anemones, including one called Anemone nemorosa ‘Stammheim’ described as “a new double bracted white-flowered form”. Reading on screen, I glossed over that, and the other eleven wood anemones listed alongside it. But when I called in at the nursery, in pursuit of a fern, Woodwardia unigemmata, there was ‘Stammheim’, waving at me as wildly as a wood anemone can, absolutely irresistible, waiting to be swooped upon. Which of course it was. I’m not made of stone. And me going out for a fern and coming back with a wood anemone is nowhere near as mad as my husband going out for a haircut and coming back with an Alfa Romeo, which is what happened this week.

The advantage of the online catalogue for a small, specialist nursery such as Long Acre Plants is that the Rowlands can use it to list plants that they don’t have many of and so don’t put in their printed catalogue. They still produce one and it’s very handsome, but once it’s been sent out, it can’t be tweaked in the way the online list can. When plants sell out they can be deleted from the website list. When seasonal things come into their own, they can be added.

The two of them met at the Royal Horticultural Society’s garden at Wisley where they had both signed on as trainee gardeners. Then they went on together to Reading University, where Michelle did a degree in landscape management and Nigel started a PhD about paeonies. Even then they ran a nursery, more of a hobby than a profession, but it taught them the vagaries of the business, the difficulties of predicting how many of which plants to grow, the trickiness of persuading some plants to live in a pot at all. Pulmonarias hate it. So does the fabulous Lilium nepalense (greenish-yellow outside, reddish-purple inside). Paris quadrifolia, the native ‘Herb Paris’, is exactly the kind of plant you’d expect to find in a nursery specializing in woodlanders, but it too, says Nigel Rowland, languishes when trapped in a pot.

I wondered how easy they found it to agree on what they should be growing. At any one time they reckon they have five or six hundred different plants on the nursery. Do they both love them all equally? There was a pause before Michelle admitted to a prejudice against plants with yellow leaves. And then another pause before she said that perhaps she wasn’t quite so mad as Nigel was about Adoxa moschatellina “a little green-flowered thing”. Generally though, given the passionate views that plant people have about the merits and failings of particular plants, they seem to be remarkably united in their choices.

I didn’t dare ask whether either had a favourite plant. It would be like asking a parent to choose a favourite among their children. But they did come up with a list of their bestsellers, a useful indicator of their customers’ favourites. It includes Anemone leveillei (£3) “basically a larger-flowered and more robust form of Anemone rivularis but without the blue anthers”; Anemonopsis macrophylla (£4.50) “a magical woodlander for cool humus-laden soils, summer flowering with crystalline pinky purple flowers over ferny foliage”; Brunnera macrophylla ‘Jack Frost’ (£4) “a new variety that shows great vigour even in dry conditions with fully silvered leaves and the typical blue flowers”; Dryopteris wallichiana (£4) “a most magnificent evergreen fern from the Himalayas and Japan with young unfolding fronds that are golden green in spring and contrast well with the hairy black midribs and stems”; Epimedium epsteinii (£5) “large pale lilac and purple flowers with brilliant leaf colour”; Epimedium x youngianum ‘Niveum’ (£3.50) “very easy with masses of pure white flowers in spring”; Erythronium californicum ‘White Beauty’ (£3); Erythronium dens-canis ‘Pink Perfection’ (£3) “mid pink-flowered form of an easy dog’s toothy violet”; Tellima grandiflora ‘Forest Frost’ (£4) “good for shade, even dry shade with pink flowers in spring and heavily mottled leaves, beautiful in winter when they turn burgundy and hold the frost.”

The problem today is the summer holidays in working London, where every neighbourly childcare arrangement that can possibly be invoked has been cranked into action to avoid forcing grannies to work more hours than the European Union will legally permit. So now I’m trying to chide not just one child but several into the shade, due to my profound fear of brûlée-ing someone to whom I’m not genetically related. “Get out of the bright sunlight!” I sob, plaintively, finger right on the trigger of the Factor 50.

Plants, of course, take an entirely different view, and most of them are quite happy to dawdle for hours, all summer long, in sunshine so unremitting that even Chris Froome and his sun-resistant superlegs would probably get a bit wobbly. And we gardeners take advantage. But there do exist those apparently unlucky gardeners whose entire gardens are in shade. “Poor them,” you will be thinking, “how will they ever get anything to grow in those rubbish conditions? Although, frankly, a bit of shade would be much nicer to sit in.” Much nicer to sit in, yes, and as it turns out, perfectly OK for gardening, too. The idea that gardens cannot flourish with full-on south-facing sunshine is a total myth propounded by people who live on the south side of the street. We north-side dwellers can tell you that for nothing.

The best thing about a north-facing garden is the cool shade, but the second-best thing is all the lovely plants that you won’t see in everyone else’s gardens. Traditionally, gardeners always choose something south-facing, or at worst, south-west, but if I had to do it all again, I would once more plump for the north-facing garden. Here there are roses, yes, roses, in flower; honeysuckles and clematis and jasmine. We’ve had plenty of shady favourites in flower already, such as foxgloves, smart French-style hydrangeas (much better in French, I always think, where they are called a hortensia); and now Japanese anemones are in bud, happily about to stud the shadows with their soft-pink petals. Plenty of soft-species geraniums, too, for bright spots of blue that zing in the dusk.

The most important thing is to work out where in your garden you have the relatively flexible moist shade, and where you have the deeply feared “dry shade”. Dry shade tends to occur under trees, next to high walls and anywhere sheltered from rain. In both cases, it’s important to know whether the spot gets any sunshine at all during the day. (I keep having money-making daydreams of going on Dragons’ Den to propose a solar-powered sun-timer that could be left on the soil for the day, which would then tell you the plants suitable for the hours of light available; but in the meantime, you need to sit out from dawn till dusk, checking.)

My biggest tip would be to use the specialists: David Austin provides lists of roses that will put up with four to six hours of sunlight a day, for example. Or settle down with the catalogue from Wincanton’s Long Acre Nursery, beautifully entitled “Plants For Shade”. There’s nine pages on ferns alone, to cool even the sweatiest gardener.

Dig in: How to plant shady areas

Keep it moist

Many shade plants will do better in moist soil, so if you are trying to make a garden work in deep north-facing shadow, dig in lots of organic material first to ensure the earth holds as much water as it can. And consider installing irrigation: especially in small shady town gardens, this can allow your sun-starved beauties to flourish regardless.

See anemones

Anemones are stars in the shade, managing glowing soft-white flowers in late summer even planted up against fences and car parks. “Honorine Jobert” AGM is a corker. £5.50

Star quality

Aster frikartii “Monch” AGM has dazzling, floaty clouds of blue starbursts, which flower for weeks through August and September. A Piet Oudolf must-have, it combines well with other late Oudolf favourites such as wheaten grasses.

White light

Geranium “Mount Olympus” AGM offers pure-white flowers above a bunchy, flourishing bump of green foliage, flowering for weeks in summer.

Best fronds

Finally, if all you have to play with, garden-wise, is a basement stairwell, turn to the ferns. Well-watered, these beautiful plants will make your dusty utility area a burst of heartening green. I love Dryopteris ‘Cristata’, the King Fern, with huge arching fronds when well irrigated.

Purple haze

Thalictrum “Black Stockings” is a willowy teenager of a plant that bears soft, hazy clusters of petals on deep-black stems up to 6ft tall. In my garden it does best with a bit of sun during the day, mostly in the shade, but planted in rich, moist soil.

Cheer up!

Alchemilla mollis AGM is the ultimate National Trust path-edger: these hard-wearing blue-green leaves with the bright-lime flowers will cheer up shady corners – even those which don’t do well water-wise.

Without the putative sycamore, north- and east-facing walls present few problems, though you may not get as colourful a display as on sunny walls. Foliage will be excellent. North walls are almost easier than east. They get no direct sun at all, though in summer a few slanting beams may drop in at the beginning and the end of the day. In a new garden, you need to spend some time watching walls and the amount of light they get before you start planting anything at all.

East walls are more treacherous. They are cold, but get a burst of sun, if there is any, at the beginning of the day – fatal to plants frosted overnight. Most people know that east walls are bad news for camellias. Other plants can react just as badly. Cells that may be frozen need to thaw out gently, just like water pipes. An early blast of sunshine may cause too quick a thaw, rupturing cell walls. Plants collapse and may die. I lost a 30-ft `Mermaid’ rose on an east wall, though it had a trunk as thick as my arm and seemed invincible. Chaenomeles and pyracantha have never been affected. More surprisingly, neither has the evergreen shrub piptanthus, with its fine, hand-shaped leaves.

The chaenomeles (japonica) is already in bloom, with blood-red flowers on dark wood. I like them spreadeagled on a wall, pinned flat and pruned fairly severely after flowering to eliminate twigs that try to push forward. This makes it easier to grow other things in front, but also seems to give it a more oriental air, like the two-dimensional branches of japonica you see in a Japanese print or a piece of fabric.

`Crimson and Gold’ is the one to go for if you like your colours rich and uncompromising. It will not grow much beyond 4ft. `Knap Hill Scarlet’ is equally brilliant. If gentle introspection is more your thing, choose the gentle, pink-and-white `Moerloosei’, fast-growing, wide-spreading, and reaching eventually to a height of 8ft, though its spread may be twice as broad as that.

Pyracantha is also best when it gets some corrective training. Some time ago, I planted one on our east wall, to the right-hand side of the kitchen window, a biggish window of old-fashioned, small square panes. Over the years I’ve trained the pyracantha to make another “window” alongside, the branches criss-crossing to make “panes” against the walls. It’s slightly dotty, but it makes me smile when I turn in at our gate. The blackbirds like it, too.

Pyracantha was one of the wows of James I’s garden, when it was a rarity newly brought in from the east. It is very popular now, and deservedly, as happy on a north wall as it is on an east one. It is evergreen and gives two meaty performances a year. I prefer it in berry to when it is in flower. Bees think otherwise. It is spiny, but not viciously so, and is not difficult to handle.

The blossom is the same on all varieties, white with a heavy, musty scent. Berries can be yellow (`Flava’ or `Soleil d’Or’), orange (`Orange Glow’ or `Orange Charmer’) or red (`Dart’s Red’ or `Watereri’). I am not fussy about the times I trim pyracanthas to shape, leaping in with the secateurs whenever the whiskers of growth start to get in the way of the chequerboard pattern.

I started by training one stem up the side of the window, then choosing horizontal branches to train out from that main stem. You have to wait for suitable growths to present themselves, but pyracantha is so vigorous that that is rarely a problem. When there were six or seven stems stretched out parallel at about 15-in intervals against the wall, I started looking for upright growths sprouting from the horizontals that would turn the straight lines into a series of squares. It is far more complicated to describe than it is to do.

Fire blight, a fungal disease that floats in on the air and ravages the foliage, is pyracantha’s worst enemy. There is no cure. But don’t lie awake worrying about this scourge. It may never happen.

Because rain tends to come in from the south and the west, north- and east-facing walls and fences act as barriers, preventing the ground under them from getting properly wetted. Wall shrubs on any aspect do better if they are planted a little distance – say, 18in – out from the wall. The ground will also retain more moisture if you dig in a good quantity of manure and compost before you plant. Mulch all wall shrubs regularly in autumn and spring.

There has been no lack of water this winter, but drought is not just a summer problem. East and north walls face winter’s coldest and most drying winds. Evergreens suffer more than deciduous shrubs. Foliage loses moisture faster than the roots can take it up. Leaves turn brown and die.

This gloomy scenario need not worry us this year, at least. Too often gardening is seen as a series of problems to be overcome rather than pleasures to be indulged. Here is an excellent pleasure for an indulgent north wall: Azara microphylla. This shrub has small dark, shining, evergreen leaves and powdery tufts of bright yellow flowers that smell strongly of vanilla.

It will not do well on excessively limey soils and may keel over completely in a tough winter. In pampered city gardens, wrapped in the central heating that escapes through windows and doors, it will thrive. It flowers in March, needs no pruning and suffers from no particular nervous tics – a paragon.

Where there is some shelter from wind, the twining climber Celastrus scandens will perform well on a north or east wall. Its season is autumn, when the orange-red seed vessels produced from insignificant flowers explode to expose startling red seeds. It is very vigorous; it likes a good mouthful of fence or porch to get its teeth into. Once established, it needs little nannying.

All these plants will give brilliance to shade. If you want something cooler, choose the white-flowered climbing Hydrangea petiolaris. Or plant the compact upright shrub Euonymus fortunei `Silver Queen’, with its fine variegated leaves. When it is established, thread it through with a pale clematis such as `Marie Boisselot’ or `Lady Northcliffe’.

Variegated Cotoneaster horizontalis is another great beauty that thrives in shade.

Make it the mantra for the year: Shade is Good.